A military vessel from Republic has crashed on a highly populated cis planet during the clone wars both sides were extremely tense. The cis had seen this as a high threat and attack the massive Republic army. And thus the chaos of war begins with you in the middle........

technically that makes him a sith soldier/general since sith don't need the force, sith lords do (I am thinking of the sith soldiers from KOTOR, who clearly did not use the force but were part of that fraction and therefore considered sith.

Sith in that context is because they're a member of a group known as the Sith Empire. Sith in any era that isn't Old Republic or Legacy are those trained in using the dark side of the Force. Since he wasn't able to use the force, he was just considered a Jedi Killer. Like my boy Tangae said.

that would require adding gloves that would make it seem as if he had 4 arms, but actualy changing it to allow 4 arms is extremely tricky with the warband code, it may be easy to reskin and add new items, but changing the actual code farther then the basic animations and sounds, as well as weapon affects like a laser shot, thats about as far as the "easy" modding of warband goes, thats what they are claiming they have changed in bannerlord.